Answer:
x=11°
<Bec = 33°
<Ced = 39°
Explanation:
That's a right angle so it would be 90 degrees angle.
18+3x+4x-5=90
Lets simplify it to make it easier to work out by collecting like terms.
First all the variable 3x+4x=7x
Then the numbers 18+-5=13
13(-13)+7x = 90(-13)take away 13 from both sides
(Opposite operators EG, Add becomes subtract)
7x = 77 then divide 7 from both sides
x=11
Then work out
3x11=33 degrees
4x11=44-5=39 degrees
To double check 39+33+18=90 degrees